pug Posted April 12, 2010 Share Posted April 12, 2010 1990 2.5 ax5. When i start it up it idles normal. Then when it warms up sitting at a stop the idle drops down around 200 rpm. Any ideas thanks Link to comment Share on other sites More sharing options...
MjAllTheWay Posted April 12, 2010 Share Posted April 12, 2010 I have the same problem but mine idles at like 400 to 500 mine is a 88 auto 4.0 trans but i can't find the problem. Link to comment Share on other sites More sharing options...
skeletor Posted April 12, 2010 Share Posted April 12, 2010 I have the same problem in my 89' 4.0. starts good, rpm shoots then settles around 4-5 sometimes going up to 5-6 but the low idle always prevails. always starts, always strong. Link to comment Share on other sites More sharing options...
MjAllTheWay Posted April 12, 2010 Share Posted April 12, 2010 I have the same problem in my 89' 4.0. starts good, rpm shoots then settles around 4-5 sometimes going up to 5-6 but the low idle always prevails. always starts, always strong. Yep mine runs good runs strong jest has a low idle. Link to comment Share on other sites More sharing options...
pug Posted April 12, 2010 Author Share Posted April 12, 2010 Does anybody know if you can adjust a tbi. I also forgot to mention it is a rough ido. thanksl Link to comment Share on other sites More sharing options...
Wildman Posted April 12, 2010 Share Posted April 12, 2010 If the IAC is good *and clean* There is a small adjustment screw on the back of the TB throttle arm that can be adjusted for idle. Seam to know someone whom used a manual TB with a AW4 swap, and had to make this adjustment :D Link to comment Share on other sites More sharing options...
pug Posted April 12, 2010 Author Share Posted April 12, 2010 Does somebody have a picture of the IAC thanks Link to comment Share on other sites More sharing options...
Wildman Posted April 13, 2010 Share Posted April 13, 2010 5th one down the list........ http://www.lunghd.com/Tech_Articles/Eng ... ostics.htm Link to comment Share on other sites More sharing options...
pug Posted April 13, 2010 Author Share Posted April 13, 2010 Just wondering would this cause low rpm and rough idel. thanks Link to comment Share on other sites More sharing options...
Wildman Posted April 13, 2010 Share Posted April 13, 2010 Generally, the IAC will cause high idle at start-up, and rough idling. Also check your MAP, make sure the vacuum line is clear and connected on both ends. Another possible cause is the EGR valve, I had one so bad, it would choke the engine right out, I disconnected it, and plugged the vacuum line *we don't have sniffer test here on anything before '96* And.......while your at it, check ALL the vacuum lines, one loose/cracked hose could cause rough idling. Link to comment Share on other sites More sharing options...
pug Posted April 13, 2010 Author Share Posted April 13, 2010 On the vacume lines were they all go together by the valve cover. Is this something i can buy at auto part store. i don't know what it is called Link to comment Share on other sites More sharing options...
Wildman Posted April 13, 2010 Share Posted April 13, 2010 On the vacume lines were they all go together by the valve cover. Is this something i can buy at auto part store. i don't know what it is called :hmm: :dunno: You mean the tree??? Where all the lines connect??? I don't think a parts store would have a part like that.........JY is your only bet. You could check the "Help" section to see first :dunno: Link to comment Share on other sites More sharing options...
pug Posted April 13, 2010 Author Share Posted April 13, 2010 I will try that. I am tired of giving it gas at a stop to keep it from dying Link to comment Share on other sites More sharing options...
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